Two months into his term as governor, there had been an early morning accident at Three Mile Island.

Thornburgh, who earned a degree in engineering before going to law school, knew immediately that this was a crisis. But with no actionable information in hand, he returned to a meeting with lawmakers while top aides worked to get a handle on the problem.

"Till I had some sense of what this involved, I didn't want to alarm anybody or comfort them," Thornburgh said in an interview recently.

Over the next five days, Thornburgh had his leadership qualities tested like few American elected officials have before or since. The rookie governor had to respond to an unprecedented technological disaster with hundreds of thousands of lives potentially hanging in the balance.

Early on, he said, he and the public were being misled by officials of Metropolitan Edison, the plant's owner at the time, who seemed most interested in saving face.

"Their credibility eroded rather quickly," Thornburgh said. "We also found out there were plenty of people around who were willing to tell us more than they knew or less than they knew. But there was no one single source that we could rely upon for an accurate assessment of precisely what happening at the plant."

Thornburgh needed information to make his call on a general evacuation of the area. It didn't get any easier through the first 48 hours.

By the incident's third day, with fears of a meltdown persisting and a Washington misinterpretation of an air sample at the site causing public concern to spike, Thornburgh recommended that pregnant women and preschoolers within five miles of the plant leave.

Friday's confusion led Thornburgh to make a direct appeal to President Jimmy Carter for an on-site manager who could help give everyone a reliable read on what they were facing. Carter sent in Harold Denton, a top official with the Nuclear Regulatory Commission.

Thornburgh considers Denton one of the heroes of the incident.

The Associated Press/1979Then-President Jimmy Carter, center right, accompanied by Harold Denton, then director of the U.S. Nuclear Agency, left, and then Pennsylvania Gov. Dick Thornburg, left-rear, tour the control room of the Three Mile Island nuclear plant in Middletown, Pa. four days after the nuclear accident.

Denton "had a very reassuring quality about him," Thornburgh recalled. "He was able to translate nuclear jargon, which few of us understood, into plain English and very quickly earned the credibility of not only our team ... but the whole state and the whole nation.

"He was able to, I think, provide a little calm in the midst of potential hysteria."

There were still some dicey moments ahead. Thornburgh remembers the "bubble scare" on Saturday, when another bad report from Washington led some news services to report incorrectly on a potentially explosive hydrogen bubble within the reactor vessel.

On Sunday, four days after the initial leak, Carter and Thornburgh toured the plant together, beaming reassuring video around the world that suggested incident managers had stabilized the problems.

It wasn't until the following Friday, however, that Thornburgh went on television to declare that the crisis was over and that all those who had left -- up to 100,000 residents -- could "come home again."

Thornburgh said that by far his toughest decision through the ordeal was whether to call for a general evacuation. Some critics say Thornburgh was reckless not to do so. But he defended the decision.

"In any evacuation ... the record's pretty clear that inevitably you're going to cause some damage to people and even loss of life, and that was not something that we wanted to risk in this situation unless it was absolutely necessary.

"I never tried to discourage people if they felt it was important for them to leave the area to do so," Thornburgh added. "But when you're talking about moving a quarter of a million people with known risks to vulnerable portions of the population, you're just not going to do that unless it's absolutely necessary."

Thornburgh's level-headed approach gave him an instant national profile. He would later serve as the U.S. attorney general under Presidents Ronald Reagan and George Bush.

Thornburgh said he liked what he learned about Pennsylvanians that week.

"Nobody panicked," Thornburgh said. "People behaved in a rational way in the face of something totally unexpected. And it just buoyed my faith in the citizens of our state."